I used Elmer's school glue to sew the circles on this quilt.
http://www.quiltingboard.com/posts/list/17782.page
I didn't use a special tip, I found if I was just a little bit careful I could get a thin bead of glue just using the tip on the bottle. I also used it on some bias binding on a set of potholders and it worked great. I'll be using it from now on instead of pins.